Liquid crystal display (LCD) is one of the most widely used panel displays. Liquid crystal display panel is the core part of the liquid crystal display. The liquid crystal display panel is usually composed of a color filter substrate (CF Substrate), a thin film transistor array substrate (TFT Array Substrate), and a liquid crystal layer disposed between the two substrates. Generally, the array substrate and the color filter substrate respectively comprise a pixel electrode and a common electrode disposed thereon. When a voltage is applied to the pixel electrode and the common electrode, an electric field is generated in the liquid crystal layer. The electric field determines the orientation of the liquid crystal molecules so as to adjust the polarization of the light incident on the liquid crystal layer. As a result, the liquid crystal display panel displays images.
Based on the operation mode of the liquid crystal, the display modes of the liquid crystal display panel are mainly separated into a phase change (PC) type, a twisted nematic (TN) type, a vertical alignment (VA) type, a in plane switching (IPS) type, and a fringe field switching (FFS) type. Among them, compared to other types of liquid crystal displays, the VA type liquid crystal display has an extremely high contrast. It is quite widely used in large-size display, such as televisions. Polymer-stabilized vertical alignment (PSVA) wide-angle technology is an improved technology of the VA type liquid crystal display panel. It can make the liquid crystal display panel have the advantages of fast response time, high transmittance rate, and so on. It is characterized by the use of an optical orientation method to form polymer protrusions on the surface of the alignment film so that the liquid crystal molecules have a pre-tilt angle.
The process of the conventional optical orientation method for a PSVA liquid crystal display panel generally comprises applying a curing voltage to a pixel electrode and a common electrode of the liquid crystal display panel. At the same time, ultraviolet (UV) light is applied to the liquid crystal display panel. By irradiating UV light, the reactive type monomer in the liquid crystal composition reacts to form polymer protrusions on the surface of the alignment film so that the liquid crystal molecules form a pre-tilt angle. According to different probe locations, there are two conventional ways to realize the application of the curing voltage to the pixel electrode and the common electrode of the liquid crystal display panel. The first type is array probe curing. A side edge of the array substrate is arranged to extend outside of the color filter substrate and be exposed from the color filter substrate. Curing pads are arranged in the extending region and electrically connected to signal input pads of each signal line (including gate lines, data lines, common electrode lines, and so on). Orientation signals are applied to each curing pad through probe pins. Accordingly, applying the curing voltage to the pixel electrode and the common electrode of the liquid crystal display panel is realized. The orientation process is finished. The second type is CF probe curing. A side edge of the color filter substrate is arranged to extend outside of the array substrate and be exposed from the array substrate. The common electrode on the color filter substrate is separated into two electrode portions. The two electrode portions are respectively connected to the signal input pads on the array substrate through two gold glue strips. Orientation signals are applied to the two electrode portions through probe pins. The orientation signals are transmitted to the signal input pads through the two gold glue strips. Accordingly, applying the curing voltage to the pixel electrode and the common electrode of the liquid crystal display panel is realized. The orientation process is finished.
Furthermore, the signal input pads on the conventional array substrate are usually uniformly arranged side by side at regular intervals. The spacing between the two adjacent signal input pads is usually about 1 mm. In the CF probe curing method, the accuracy of coating the gold glue has a limitation. There may be a short circuiting between the gold glue strips connecting different electrode portions. As a result, the orientation may be poor. However, if the pitch between the signal input pads is increased (generally more than 10 mm is needed to effectively avoid short circuiting), the signal input pads occupy too much design space. The complexity of the probe bar is increased.